/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the  "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id$
 */
package wx.xml.xalan.xml.utils;

/**
 * A very simple table that stores a list of int.
 * <p>
 * This version is based on a "realloc" strategy -- a simle array is
 * used, and when more storage is needed, a larger array is obtained
 * and all existing data is recopied into it. As a result, read/write
 * access to existing nodes is O(1) fast but appending may be O(N**2)
 * slow. See also SuballocatedIntVector.
 *
 * @xsl.usage internal
 */
public class IntVector implements Cloneable {

    /**
     * Size of blocks to allocate
     */
    protected int m_blocksize;

    /**
     * Array of ints
     */
    protected int m_map[]; // IntStack is trying to see this directly

    /**
     * Number of ints in array
     */
    protected int m_firstFree = 0;

    /**
     * Size of array
     */
    protected int m_mapSize;

    /**
     * Default constructor.  Note that the default
     * block size is very small, for small lists.
     */
    public IntVector() {

        m_blocksize = 32;
        m_mapSize = m_blocksize;
        m_map = new int[m_blocksize];
    }

    /**
     * Construct a IntVector, using the given block size.
     *
     * @param blocksize Size of block to allocate
     */
    public IntVector(int blocksize) {

        m_blocksize = blocksize;
        m_mapSize = blocksize;
        m_map = new int[blocksize];
    }

    /**
     * Construct a IntVector, using the given block size.
     *
     * @param blocksize Size of block to allocate
     */
    public IntVector(int blocksize, int increaseSize) {

        m_blocksize = increaseSize;
        m_mapSize = blocksize;
        m_map = new int[blocksize];
    }

    /**
     * Copy constructor for IntVector
     *
     * @param v Existing IntVector to copy
     */
    public IntVector(IntVector v) {
        m_map = new int[v.m_mapSize];
        m_mapSize = v.m_mapSize;
        m_firstFree = v.m_firstFree;
        m_blocksize = v.m_blocksize;
        System.arraycopy(v.m_map, 0, m_map, 0, m_firstFree);
    }

    /**
     * Get the length of the list.
     *
     * @return length of the list
     */
    public final int size() {
        return m_firstFree;
    }

    /**
     * Get the length of the list.
     *
     * @return length of the list
     */
    public final void setSize(int sz) {
        m_firstFree = sz;
    }


    /**
     * Append a int onto the vector.
     *
     * @param value Int to add to the list
     */
    public final void addElement(int value) {

        if ((m_firstFree + 1) >= m_mapSize) {
            m_mapSize += m_blocksize;

            int newMap[] = new int[m_mapSize];

            System.arraycopy(m_map, 0, newMap, 0, m_firstFree + 1);

            m_map = newMap;
        }

        m_map[m_firstFree] = value;

        m_firstFree++;
    }

    /**
     * Append several int values onto the vector.
     *
     * @param value Int to add to the list
     */
    public final void addElements(int value, int numberOfElements) {

        if ((m_firstFree + numberOfElements) >= m_mapSize) {
            m_mapSize += (m_blocksize + numberOfElements);

            int newMap[] = new int[m_mapSize];

            System.arraycopy(m_map, 0, newMap, 0, m_firstFree + 1);

            m_map = newMap;
        }

        for (int i = 0; i < numberOfElements; i++) {
            m_map[m_firstFree] = value;
            m_firstFree++;
        }
    }

    /**
     * Append several slots onto the vector, but do not set the values.
     *
     * @param numberOfElements Int to add to the list
     */
    public final void addElements(int numberOfElements) {

        if ((m_firstFree + numberOfElements) >= m_mapSize) {
            m_mapSize += (m_blocksize + numberOfElements);

            int newMap[] = new int[m_mapSize];

            System.arraycopy(m_map, 0, newMap, 0, m_firstFree + 1);

            m_map = newMap;
        }

        m_firstFree += numberOfElements;
    }


    /**
     * Inserts the specified node in this vector at the specified index.
     * Each component in this vector with an index greater or equal to
     * the specified index is shifted upward to have an index one greater
     * than the value it had previously.
     *
     * @param value Int to insert
     * @param at    Index of where to insert
     */
    public final void insertElementAt(int value, int at) {

        if ((m_firstFree + 1) >= m_mapSize) {
            m_mapSize += m_blocksize;

            int newMap[] = new int[m_mapSize];

            System.arraycopy(m_map, 0, newMap, 0, m_firstFree + 1);

            m_map = newMap;
        }

        if (at <= (m_firstFree - 1)) {
            System.arraycopy(m_map, at, m_map, at + 1, m_firstFree - at);
        }

        m_map[at] = value;

        m_firstFree++;
    }

    /**
     * Inserts the specified node in this vector at the specified index.
     * Each component in this vector with an index greater or equal to
     * the specified index is shifted upward to have an index one greater
     * than the value it had previously.
     */
    public final void removeAllElements() {

        for (int i = 0; i < m_firstFree; i++) {
            m_map[i] = java.lang.Integer.MIN_VALUE;
        }

        m_firstFree = 0;
    }

    /**
     * Removes the first occurrence of the argument from this vector.
     * If the object is found in this vector, each component in the vector
     * with an index greater or equal to the object's index is shifted
     * downward to have an index one smaller than the value it had
     * previously.
     *
     * @param s Int to remove from array
     * @return True if the int was removed, false if it was not found
     */
    public final boolean removeElement(int s) {

        for (int i = 0; i < m_firstFree; i++) {
            if (m_map[i] == s) {
                if ((i + 1) < m_firstFree)
                    System.arraycopy(m_map, i + 1, m_map, i - 1, m_firstFree - i);
                else
                    m_map[i] = java.lang.Integer.MIN_VALUE;

                m_firstFree--;

                return true;
            }
        }

        return false;
    }

    /**
     * Deletes the component at the specified index. Each component in
     * this vector with an index greater or equal to the specified
     * index is shifted downward to have an index one smaller than
     * the value it had previously.
     *
     * @param i index of where to remove and int
     */
    public final void removeElementAt(int i) {

        if (i > m_firstFree)
            System.arraycopy(m_map, i + 1, m_map, i, m_firstFree);
        else
            m_map[i] = java.lang.Integer.MIN_VALUE;

        m_firstFree--;
    }

    /**
     * Sets the component at the specified index of this vector to be the
     * specified object. The previous component at that position is discarded.
     * <p>
     * The index must be a value greater than or equal to 0 and less
     * than the current size of the vector.
     *
     * @param value object to set
     * @param index Index of where to set the object
     */
    public final void setElementAt(int value, int index) {
        m_map[index] = value;
    }

    /**
     * Get the nth element.
     *
     * @param i index of object to get
     * @return object at given index
     */
    public final int elementAt(int i) {
        return m_map[i];
    }

    /**
     * Tell if the table contains the given node.
     *
     * @param s object to look for
     * @return true if the object is in the list
     */
    public final boolean contains(int s) {

        for (int i = 0; i < m_firstFree; i++) {
            if (m_map[i] == s)
                return true;
        }

        return false;
    }

    /**
     * Searches for the first occurence of the given argument,
     * beginning the search at index, and testing for equality
     * using the equals method.
     *
     * @param elem  object to look for
     * @param index Index of where to begin search
     * @return the index of the first occurrence of the object
     * argument in this vector at position index or later in the
     * vector; returns -1 if the object is not found.
     */
    public final int indexOf(int elem, int index) {

        for (int i = index; i < m_firstFree; i++) {
            if (m_map[i] == elem)
                return i;
        }

        return java.lang.Integer.MIN_VALUE;
    }

    /**
     * Searches for the first occurence of the given argument,
     * beginning the search at index, and testing for equality
     * using the equals method.
     *
     * @param elem object to look for
     * @return the index of the first occurrence of the object
     * argument in this vector at position index or later in the
     * vector; returns -1 if the object is not found.
     */
    public final int indexOf(int elem) {

        for (int i = 0; i < m_firstFree; i++) {
            if (m_map[i] == elem)
                return i;
        }

        return java.lang.Integer.MIN_VALUE;
    }

    /**
     * Searches for the first occurence of the given argument,
     * beginning the search at index, and testing for equality
     * using the equals method.
     *
     * @param elem Object to look for
     * @return the index of the first occurrence of the object
     * argument in this vector at position index or later in the
     * vector; returns -1 if the object is not found.
     */
    public final int lastIndexOf(int elem) {

        for (int i = (m_firstFree - 1); i >= 0; i--) {
            if (m_map[i] == elem)
                return i;
        }

        return java.lang.Integer.MIN_VALUE;
    }

    /**
     * Returns clone of current IntVector
     *
     * @return clone of current IntVector
     */
    public Object clone()
        throws CloneNotSupportedException {
        return new IntVector(this);
    }

}
